Add placeholder color for Compose manga covers

app/src/main/java/eu/kanade/tachiyomi/ui/manga/info/MangaCoverImageView.kt

@@ -1,24 +0,0 @@
-package eu.kanade.tachiyomi.ui.manga.info
-
-import android.content.Context
-import android.util.AttributeSet
-import androidx.appcompat.widget.AppCompatImageView
-import kotlin.math.min
-
-/**
- * A custom ImageView for holding a manga cover with:
- * - width: min(maxWidth attr, 33% of parent width)
- * - height: 2:3 width:height ratio
- *
- * Should be defined with a width of match_parent.
- */
-class MangaCoverImageView(context: Context, attrs: AttributeSet?) : AppCompatImageView(context, attrs) {
-
-    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
-        super.onMeasure(widthMeasureSpec, heightMeasureSpec)
-
-        val width = min(maxWidth, measuredWidth / 3)
-        val height = width / 2 * 3
-        setMeasuredDimension(width, height)
-    }
-}